Reaction #93189

Reaction equation

3-(Acetylthio)propanoic acid

glycolic acid

triethylamine

→

O-(3-Acetylthiopropanoyl)glycolic Acid

Solvents

tetrahydrofuran

tetrahydrofuran

Conditions

Workup

1. 1
   workup.WAITAfter twenty minutes
2. 2
   OtherThe tetrahydrofuran is removed in vacuo
3. 3
   Washwashed with 1N hydrochloric acid and three times with water
4. 4
   Dryingdried over magnesium sulfate
5. 5
   Concentrationthe O-(3-acetylthiopropanoyl)glycolic acid is concentrated to dryness in vacuo, yield 3.9 g
6. 6
   workup.DISSOLUTIONThis is dissolved in ether
7. 7
   workup.ADDITIONdicyclohexylamine is added
8. 8
   OtherThe dicyclohexylamine salt precipitates
9. 9
   workup.ADDITIONby adding to ethyl acetate
10. 10
    workup.ADDITIONadding 10% potassium bisulfate solution, yield 1.5 g

Procedure

3-(Acetylthio)propanoic acid (2.96 g) and 1,1'-carboxyldiimidazole (3.24 g) are dissolved in 20 ml of dry tetrahydrofuran with stirring at room temperature. After twenty minutes, a solution of glycolic acid (1.52 g) and 2.80 ml of triethylamine in 15 ml of dry tetrahydrofuran are added. The reaction mixture is stored overnight at room temperature. The tetrahydrofuran is removed in vacuo, the crude residue taken up into ethyl acetate, washed with 1N hydrochloric acid and three times with water, dried over magnesium sulfate and the O-(3-acetylthiopropanoyl)glycolic acid is concentrated to dryness in vacuo, yield 3.9 g. This is dissolved in ether and dicyclohexylamine is added. The dicyclohexylamine salt precipitates, yield 2.85 g.; m.p. 150-157° . The salt is converted to the free acid by adding to ethyl acetate and adding 10% potassium bisulfate solution, yield 1.5 g.

Source